Impact of Pratylenchus penetrans on established red raspberry productivity

Authors: HAN, Z - Washington State University; WALTERS, T - Washington State University; Zasada, Inga

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/25/2014
Publication Date: 11/1/2014
Citation: Han, Z., Walters, T.W., Zasada, I.A. 2014. Impact of Pratylenchus penetrans on established red raspberry productivity. Plant Disease. 98:1514-1520.

Interpretive Summary: Plant-parasitic nematodes are microscopic soil worms that attack raspberry plants and cause significant loss in yield to this crop annually. Raspberry farmers face an enormous problem because they lack effective ways of reducing the numbers of nematodes in soil after a raspberry crop has been planted. This research was conducted to determine if raspberry cultivars differ in response to root lesion nematode feeding and if control of this nematode is necessary after plant establishment. In five trials raspberry cultivars were protected or not from the root lesion nematode and plant productivity and nematode populations monitored over a three year period. There were few observable difference in yield, fruit quality, or root weight between raspberry cultivars that had no nematodes compared to those that had nematodes. These results are significant because they demonstrate there is little or no benefit to managing root lesion nematodes after initial plant establishment in raspberry plantings with rotations less than 5 or 6 years. This research will be by used scientists and farmers to manage root lesion nematode in established raspberry fields.

Technical Abstract: Pratylenchus penetrans is a major constraint to the production of red raspberries. A better understanding of the damage potential of this nematode to raspberry is necessary to guide future management recommendations. The objective of this research was to determine whether several popular raspberry cultivars in Washington, Cascade Bounty, Chemainus, Meeker and Saanich, differ in susceptibility to P. penetrans and whether post-plant nematicides treatments are warranted. Field trials in existing plantings of these cultivars were established in northwest Washington. Treated plots were protected from P. penetrans by applying nematicides over a three year period, while non-treated plots received no nematicides. Pratylenchus penetrans population densities in soil and root samples were assessed spring and fall of each year. In addition, impact of P. penetrans on raspberry productivity was determined by measuring yield, fruit quality, primocane number and height, root biomass, and total plant productivity. Pratylenchus penetrans root population densities in nematicide-treated plots were consistently lower than those in non-treated plots at all the samplings. There were few consistent above-ground trends of protecting the raspberry cultivars from P. penetrans; in fact, when difference were observed treated plants yielded less than corresponding non-treated plants indicating that the nematicides may have been phytotoxic to some of the cultivars. Below-ground, there were also few consistent differences in fine root biomass, the preferred feeding site for P. penetrans, between treatments. However, this may have been due to sampling methodology because a destructive sampling of one of the cultivars did show significant differences in fine root biomass between treated and non-treated plants. Based on the current cropping system in Washington, in which growers replant raspberries every six to eight years, this study suggests that post-plant nematicide applications are of limited benefit in improving plant productivity.